1. Technical Field
The present invention relates to integrated circuits in general, and in particular to integrated circuits having electronic and photonic devices. Still more particularly, the present invention relates to a method for fabricating electronic and photonic devices on a semiconductor substrate using complementary-metal oxide semiconductor (CMOS) technology.
2. Description of Related Art
Photonics is the science of molding the flow of light. Photonic band gap (PBG) materials are a new class of dielectrics that carry the concept of molding the flow of light to its ultimate level by facilitating the coherent localization of light. Light localization within a PBG material allows the realization of high-quality micro devices and the integration of such devices through a network of microscopic waveguide channels within a single all-optical microchip. Since light is caged within the dielectric microstructure, it cannot scatter into unwanted modes of free propagation and is forced to flow along engineered defect channels between the desired circuit elements. PBG materials, infiltrated with suitable liquid crystals, may exhibit fully tunable photonic band structures that enable the steering of light flow by an external voltage.
The single biggest obstacle to the realization of the above-mentioned photonic capabilities is the lack of a proven process for synthesizing high-quality, very large-scale PBG materials with significant electromagnetic gaps at micron and sub-micron wavelengths. One very promising PBG material that can be utilized to produce photonic devices is silicon. Producing photonic devices from silicon-based photonic crystals would be a very significant commercial advantage. However, silicon-based photonic devices tend to require a relatively large area on a substrate, which becomes a hurdle for integrating photonic devices with standard electronic devices on a single silicon substrate.
Consequently, it would be desirable to provide an improved method for fabricating photonic devices on a semiconductor substrate to allow the integration of electronic and photonic devices on the same semiconductor substrate.